This invention relates generally to test handler systems for semiconductor integrated circuit (IC) devices. More particularly, it relates to a ground check system used with a test handler for checking automatically the grounding of the equipment and for shutting down the same if a grounding malfunction exists.
As is generally well-known, there has been a trend in recent years of manufacturing semiconductor integrated circuit devices with smaller and smaller physical size dimensions. In fact, the semiconductor integrated circuit devices have become so miniaturized so as to contain hundreds or thousands of circuit elements formed on a single semiconductor substrate. Along with these technical advances made in the manufacturing process, there have also been developed test equipment so as to test the semiconductor integrated circuit devices accurately, reliably and at a high rate in order to determine the quality of the devices being manufactured prior to shipment to a customer.
Therefore, various types of automatic testing and handling equipment have been developed to handle the semiconductor integrated circuit devices during the testing process. For example, there are known in the art of automatic, high volume handling systems which include an input module for loading the semiconductor integrated circuit devices and for moving them into contact with a testing device and a sort module for sorting the tested devices based upon the test results. Such prior art test handler systems are manufactured and sold by Delta-Design, Inc. of San Diego, Calif., under their Model Nos. 1210, 1220, and 1240.
It is also known that during the assembly of the semiconductor I.C. devices they are very susceptible to electrostatic discharge (ESD) which may cause damage to the devices and/or even destroy them completely. Thus, it is very important to be able to strictly control the ESD voltage in the manufacturing process. Further, in the test handler system used for testing of the devices there are various moving parts such as the input heads of a xe2x80x9cpick and placexe2x80x9d mechanism and the input quad arm in the input module which are potential sources of electrostatic discharge. In addition, the output heads, the sleeve pusher, and the output retriever board of the sort module of the test handler system may also cause problems due to the ESD voltage. Consequently, all of these moving parts are required to be grounded so as to eliminate the ESD voltage that is created during their operation.
However, in view of the fact that these various parts are moving, their grounding wires are very susceptible to becoming loose or damaged. At present, there does not exist a satisfactory indication means in the prior art test handler systems for informing an operator whether the grounding wires are actually positioned in their proper position and are functioning under normal conditions. Therefore, it would be desirable to provide a ground check system for use with a test handler that would alert an operator when the ESD voltage has not been properly neutralized through the grounding wires of the equipment parts. Further, it would be expedient that the ground check system be capable of immediately terminating the devices from being loaded into the equipment.
Accordingly, it is a general object of the present invention to provide a ground check system used with a test handler for checking automatically the grounding of the equipment which has traditionally been unavailable heretofore.
It is an object of the present invention to provide a ground check system used with a test handler for checking automatically the grounding of the equipment and for shutting down the same if a grounding malfunction exists.
It is another object of the present invention to provide a ground check system for use with a test handler that would alert an operator when the ESD voltage has not been properly neutralized through the grounding wires of the equipment.
It is still another object of the present invention to provide a ground check system which includes means for terminating the devices from being loaded into the equipment if a grounding malfunction exists.
It is yet still another object of the present invention to provide a ground check system which includes visual indicator means for alerting an operator that a grounding wire is not functioning properly.
In a preferred embodiment of the present invention, there is provided a ground check system used with an input module and/or sort module of a test handler for checking automatically grounding wires associated with moving parts thereof. The ground check system includes a sensing circuit which is responsive to an ESD voltage associated with the grounding wires and to a fixed reference voltage for generating an output voltage. A visual indicator device is mounted on the input and/or sort module of the test handler and is responsive to the output voltage for alerting an operator of a malfunction in the grounding wires. An output buffer section is also responsive to the output voltage and is used to shut down the input and/or sort module when there is a malfunction in the grounding wires.